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locked Venice evaluation

Colin Elves
 

The problem is: +5 stops might not actually be enough to push the Alexa to breaking point. 

I’ve done some comparison testing myself, but since I’m in the bush leagues and not the premiership like yourself the only rough corollaries I have are the C200, UMP and the Amira. 

In my testing the C200 and UMP clipped a  stop sooner than the Amira (I actually measured it as 5/6th of a stop with the Sekonic Exposure target).

In the EXRs from your tests the C200 and UMP both held data at +3.5 and were clipped at +4. 

So you could maybe assume the Alexa might hold at +4.5 and clip at +5. 

But... given potential differences in light (and how that impacts the colour channels) and the possibility that an Alexa Shooting Raw holds a touch more than an Amira Shooting ProRes - the Alexa might well still hold at +5 and need to be pushed to +5.5 before it clips. 

Taking these corollaries at face value it looks like the Venice maybe has half a stop more headroom than the C200/UMP. Which puts it in the region of the EVA1 and FS7 in my tests (although neither of them look quite as good 5 stops under)

But this also means it has potentially half a stop less headroom than the Alexa: so when you adjust for that and compare the Alexa at -3.5 with the Venice at -4 it doesn’t look quite as good (although still impressive since it’s comparing 3.2k with 6K).

It’d be great to check the Varicam again as well. Since my understanding is that it has half a stop more headroom than the EVA1 - so may put it in line with the Alexa in this regard. And that base ISO 5000 sure is tempting for night shoots (as is the 4K S35 Sensor).

Colin Elves
Director of Photography
London/Berlin

On 25 Mar 2018, at 16:50, Geoff Boyle <geoff.cml@...> wrote:

I’m amazed you got the difference at +4, I’m sure I didn’t see it when I did the tests, Ah well, I’m wrong.

 

I will do all future tests at +/- 5 stops

 

It’s complicated, time consuming and expensive to do these tests.

 

me@...
 

@ Colin: So you’re saying the VENICE is only marginally better than the FS7? That’s a mighty big jump in cost for only small bumps in image quality. I’m not saying you’re wrong OR right - just asking for clarification. I’ve been weighing out either the VENICE or Amira and I’m having difficulty coming to a conclusion is why I ask. 

You also appear to be separating the Alexa and Amira in terms of performance but wouldn’t they be the same? Given, of course, they’re both shooting ProRes / Raw?
--
- Jeremey

alister@...
 



On 25 Mar 2018, at 21:48, me@... wrote:

@ Colin: So you’re saying the VENICE is only marginally better than the FS7? That’s a mighty big jump in cost for only small bumps in image quality. I’m not saying you’re wrong OR right - just asking for clarification. I’ve been weighing out either the VENICE or Amira and I’m having difficulty coming to a conclusion is why I ask. 

You also appear to be separating the Alexa and Amira in terms of performance but wouldn’t they be the same? Given, of course, they’re both shooting ProRes / Raw?
--
- JeremeyJ

Just remember that dynamic range is a combination of both highlight and shadow range, so you need to look at both ends. 

Also there is more to “better” images than just the easily measurable aspects. What the pictures actually look like is a huge deal. 

You’re unlikely to get any huge difference between any of these cameras as the underlying sensor tech is pretty similar for all of them, so any differences will be small and may be subtle, but often it’s the subtleties that make all the difference between a good image and a great image.


Alister Chapman

DoP - Stereographer
UK Mobile +44 7711 152226
US Mobile +1(216)298-1977


www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.















Colin Elves
 

All I’m doing is trying to extrapolate from a know known (the relative DR of the FS7 and Amira) to a known unknown (the relative DR of the Venice and Alexa) and that maybe the headroom on the Venice at ISO 500 is about the same as the FS7/F5 when shot at their native ISO of 2000.

But I guess that’s just where Sony have chosen to put it. As other’s have said they tend to think they need to overexpose the FS7/F5 by a couple of stops to get reasonably clean images. If that’s no longer necessary on the Venice (and Noise does seem to be markedly improved) and noise performance is the same under ISO 500 as the FS7 exposed at ISO 500 - then that’s an improvement of 2 stops, no? Or maybe it’s something in between.

Still. The Venice does seem to have more better noise and substantially better colour science - which is notoriously mediocre on the FS7.

In terms of whether or not these improvements are marginal. I guess that’s up to you! Who knows. You could argue that the F5 offers only marginal improvements over the FS7 (especially since they have the same sensor), for, what? Twice the price. But many people are happy to pay that price to get those improvements. 🤷‍♂️

I guess there’s two ways of looking at it: if production is renting the cameras, then get the best you can and only worry about the price if it impacts your budget negatively in other areas.

And if you’re buying it for yourself... spend the least you can to deliver the best images you can! In which case any such improvements probably can be considered marginal.

Colin Elves
Director of Photography
Berlin/London

On 25 Mar 2018, at 22:48, me@... wrote:

@ Colin: So you’re saying the VENICE is only marginally better than the FS7? That’s a mighty big jump in cost for only small bumps in image quality. I’m not saying you’re wrong OR right - just asking for clarification. I’ve been weighing out either the VENICE or Amira and I’m having difficulty coming to a conclusion is why I ask.

Art Adams
 


But I guess that’s just where Sony have chosen to put it.

A Sony rep told someone at a local rental house that 500 was the sweet spot that gave them the best combination of noise vs. color vs. dynamic range. That's completely valid.

I do wish we'd get away from using ISO and switch to EI, the way Arri uses it. EI means "Set your meter to this and you'll get predictable results." ISO is a standard, but in theory there's only one standard per camera, so as soon as you set a different "ISO" on the camera the standard is out the window. And the standard is so malleable—or so I've been told—that it's effectively meaningless.

It's similar to rating a Kodak film stock at 500 vs. rating a Fuji film stock at 500. The Fuji stock was always way noisier and they generally wanted 2/3 stop overexposure, but both (years ago) had the same ISO rating. That's why it was refreshing when Kodak switched to EI, which meant "This isn't really a standard but we think it's where the film works best."
 
then that’s an improvement of 2 stops, no? Or maybe it’s something in between.

I've found Sony cameras generally want a stop of overexposure. And it's entirely possible that rating the camera at 500 builds that in vs. the other cameras.

If Geoff's tests are indicative of how the Venice works then the noise does seem cleaner. It reminds me a little of Fujifilm still camera noise, which is luma only and looks like clumps of grain. I won't say Venice noise clumps but it does look pretty clean.
 
Still. The Venice does seem to have more better noise and substantially better colour science - which is notoriously mediocre on the FS7.

The F5 and the FS7 are based on the F3 CFA and sensor, which yields "better than Rec 709" color. That's not very good. Specifically, there's a weird non-linear magenta shift in the mid-tones that can't be easily removed, at least in Cine-EI mode. I've often wondered if Cine-EI was made for the F55 and then tacked on to the F5/FS7 without much tweaking.
 
You could argue that the F5 offers only marginal improvements over the FS7 (especially since they have the same sensor), for, what? Twice the price.

The improvements are all hardware related. They look exactly the same.

--
Art Adams
Director of Photography
San Francisco Bay Area

Colin Elves
 

On 26 Mar 2018, at 17:41, Art Adams <art.cml.only@...> wrote:

A Sony rep told someone at a local rental house that 500 was the sweet spot that gave them the best combination of noise vs. color vs. dynamic range. That's completely valid.


Sure. But still fairly arbitrary. 

I’m sure they put the F5 at 2000 because they thought that was the sweet spot too - but it seems everyone who actually used it disagreed.

Not that I’m saying most people won’t be happy with the 500. From what I can see the noise 3 under looks fairly similar to 3 under on the Varicam @800 and 3 under on the Alexa @800. Quite possibly to 3 under on the F5 (I dunno, I haven’t downloaded those yet.)

But that’s why we run these tests, right? So we can make our own minds up about where we feel the sweet spot is - and thankfully most of them have some form of user LUT you can throw on to get it looking ‘correct’ for the director afterwards. And if not there’s always the Odyssey!

It seems to me the manufacturer’s own ISO ratings are only ever there for the less technically minded who just want to know how to expose the damn things and get reasonable results (them and the marketing departments)

You could argue that the F5 offers only marginal improvements over the FS7 (especially since they have the same sensor), for, what? Twice the price.

The improvements are all hardware related. They look exactly the same.

Sure. But who am I to say whether these are marginal or not? Some people will consider them essential, others overpriced luxuries. 

I always find it hard when people ask me for advice what the ‘best’ camera is for them - as it so much depends on individual needs and tastes. They may as well ask me what hat is best for them!

Colin Elves
Director of Photography
Berlin/London


Steve Shaw
 

We do not recommend BT1886 for display calibration, as the 'variable'
component is ill thought-out.
It will 'wash-out' shadows on displays with blacks that are not close to
zero.

We recommend all calibration to be standardised at 2.4 gamma for Rec709, as
that is the 'underlying' target of BT1886, and is now also targeted for
Rec709.
sRGB is a 2.2 gamma for display calibration - the 'compound' encoding gamma
is for, well, encoding (capture).

Gamma 2.4 is standard for Reference Viewing Environments, with a surround
illumination of 10% of peak display luma (so 10 nits, as 100 nits is the
peak luma for Rec709).
(SMTE have tried to alter this to 5 nits regardless, but that is excessively
low, and is based on the needs of PQ based HDR, where the EOTF crushed
blacks causing them to be wiped-out in brighter environments.)

In Home Viewing Environments a lower gamma can be used (2.2 for example) to
attempt to overcome the brighter viewing environments, but should not be
relied on for any colour critical environments.

For any colour critical viewing you must manage the environment, not alter
the gamma.

Steve

Steve Shaw
LIGHT ILLUSION
steve@...
+44 (0)7765 400 908
www.lightillusion.com

Art Adams
 



It seems to me the manufacturer’s own ISO ratings are only ever there for the less technically minded who just want to know how to expose the damn things and get reasonable results (them and the marketing departments)

It's mostly marketing, but yes. Just saying that their reasoning for determining an EI/ISO/EIEIO is just as valid as any other. Whether it works for the user is another question.
 
Sure. But who am I to say whether these are marginal or not? Some people will consider them essential, others overpriced luxuries. 

Right, but I was only talking about the look.

--
Art Adams
Director of Photography
San Francisco Bay Area

Bruce Alan Greene
 

Hi Steve, I have a kind of non-technical observation.

When viewing Arri LogC through the Arri-REC709 LUT, it seems to me that it “fits” better into gamma 2.2 than gamma 2.4  

I’m not sure how one can really measure this in a scientific way, but I find that working in gamma 2.4 using this transform, I’m often using a gamma adjustment after the LUT conversion to 2.4, but not if my display is at 2.2…

What do you think Steve?  Are the Arri LogC to REC709 LUTs really built for gamma 2.2?  Is there really anyway to know this as camera exposure really effects the result as well…?

Bruce Alan Greene
DP Los Angeles


On Mar 26, 2018, at 11:06 AM, Steve Shaw <steve@...> wrote:

We do not recommend BT1886 for display calibration, as the 'variable'
component is ill thought-out.
It will 'wash-out' shadows on displays with blacks that are not close to
zero.

We recommend all calibration to be standardised at 2.4 gamma for Rec709, as
that is the 'underlying' target of BT1886, and is now also targeted for
Rec709.
sRGB is a 2.2 gamma for display calibration - the 'compound' encoding gamma
is for, well, encoding (capture).

Gamma 2.4 is standard for Reference Viewing Environments, with a surround
illumination of 10% of peak display luma (so 10 nits, as 100 nits is the
peak luma for Rec709).
(SMTE have tried to alter this to 5 nits regardless, but that is excessively
low, and is based on the needs of PQ based HDR, where the EOTF crushed
blacks causing them to be wiped-out in brighter environments.)

In Home Viewing Environments a lower gamma can be used (2.2 for example) to
attempt to overcome the brighter viewing environments, but should not be
relied on for any colour critical environments.

For any colour critical viewing you must manage the environment, not alter
the gamma.

Steve

Steve Shaw
LIGHT ILLUSION
steve@...
+44 (0)7765 400 908
www.lightillusion.com

 

Thanks Steve.. That answered my question on Post-VFX :-)

Michael Sanders
London Based DP.

+ 44 (0) 7976 269818




On 26 Mar 2018, at 19:06, Steve Shaw <steve@...> wrote:

We do not recommend BT1886 for display calibration, as the 'variable'
component is ill thought-out.
It will 'wash-out' shadows on displays with blacks that are not close to
zero.

David Fuller
 

Art, isn’t this just semantics? By that I mean that ASA and EI refer to the same thing—or at least as I understand them they do—only ASA is the manufacturer’s recommendation and EI is “what i set my meter to.” In the film days, I often had a different EI from the manufacturer’s ASA rating. Is that different from what you’re saying or is there more to it that I’m not understanding?


David Fuller
Director, Cinematographer, Camera Geek
Maine, USA

---

On Mar 26, 2018, at 12:41 PM, Art Adams <art.cml.only@...> wrote:

I do wish we'd get away from using ISO and switch to EI, the way Arri uses it. EI means "Set your meter to this and you'll get predictable results." ISO is a standard, but in theory there's only one standard per camera, so as soon as you set a different "ISO" on the camera the standard is out the window. And the standard is so malleable—or so I've been told—that it's effectively meaningless.

alister@...
 

If Resolve is using an official Sony SDK and Sony IDT’s, perhaps then Nick Shaw can explain why he created and sells DCTL’s based on the official Sony Transforms for S-Log3 to replace the ones that are in Resolve? And before anyone says — this isn’t S-Log3, it X-OCN, sure I know that, but it’s begs the question - why should this even be necessary if Resolve uses the official Sony tools? 

Nick? Why is this necessary is there something up with the built in Resolve transforms, are they not to spec?


Alister Chapman

DoP - Stereographer
UK Mobile +44 7711 152226
US Mobile +1(216)298-1977


www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.

















On 27 Mar 2018, at 01:14, David Fuller <david@...> wrote:

Art, isn’t this just semantics? By that I mean that ASA and EI refer to the same thing—or at least as I understand them they do—only ASA is the manufacturer’s recommendation and EI is “what i set my meter to.” In the film days, I often had a different EI from the manufacturer’s ASA rating. Is that different from what you’re saying or is there more to it that I’m not understanding?


David Fuller
Director, Cinematographer, Camera Geek
Maine, USA

---

On Mar 26, 2018, at 12:41 PM, Art Adams <art.cml.only@...> wrote:

I do wish we'd get away from using ISO and switch to EI, the way Arri uses it. EI means "Set your meter to this and you'll get predictable results." ISO is a standard, but in theory there's only one standard per camera, so as soon as you set a different "ISO" on the camera the standard is out the window. And the standard is so malleable—or so I've been told—that it's effectively meaningless.


Geoff Boyle
 

Stop this now!

 

Cheers

 

Geoff Boyle NSC FBKS

Cinematographer

Zoetermeer

www.gboyle.co.uk

+31 (0) 637 155 076

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of alister@...
Sent: 27 March 2018 06:59
To: cml-raw-log-hdr@...
Subject: Re: [raw-log-hdr] Venice evaluation

 

If Resolve is using an official Sony SDK and Sony IDT’s, perhaps then Nick Shaw can explain why he created and sells DCTL’s based on the official Sony Transforms for S-Log3 to replace the ones that are in Resolve? And before anyone says — this isn’t S-Log3, it X-OCN, sure I know that, but it’s begs the question - why should this even be necessary if Resolve uses the official Sony tools? 

 

Nick? Why is this necessary is there something up with the built in Resolve transforms, are they not to spec?

 

 

Alister Chapman

 

DoP - Stereographer

UK Mobile +44 7711 152226

US Mobile +1(216)298-1977

 

 

www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



On 27 Mar 2018, at 01:14, David Fuller <david@...> wrote:

 

Art, isn’t this just semantics? By that I mean that ASA and EI refer to the same thing—or at least as I understand them they do—only ASA is the manufacturer’s recommendation and EI is “what i set my meter to.” In the film days, I often had a different EI from the manufacturer’s ASA rating. Is that different from what you’re saying or is there more to it that I’m not understanding?

 


David Fuller

Director, Cinematographer, Camera Geek

Maine, USA

 

---

 

On Mar 26, 2018, at 12:41 PM, Art Adams <art.cml.only@...> wrote:

 

I do wish we'd get away from using ISO and switch to EI, the way Arri uses it. EI means "Set your meter to this and you'll get predictable results." ISO is a standard, but in theory there's only one standard per camera, so as soon as you set a different "ISO" on the camera the standard is out the window. And the standard is so malleable—or so I've been told—that it's effectively meaningless.

 

 

 

Nick Shaw
 

On 27 Mar 2018, at 05:58, alister@... wrote:

Nick? Why is this necessary is there something up with the built in Resolve transforms, are they not to spec?

Yes, there have been bugs in Resolve. Just like any piece of software. At one point they did appear to use an incorrect matrix for S-Gamut3.Cine, but they have fixed it, after I (and I'm sure others) reported the bug to them. The DCTL was a useful stop gap before it was fixed. I still sell it for people using older versions of Resolve (but make that clear to people before they buy).

In fact I first wrote the DCTL before the S-Gamut3.Cine IDT was published (as part of the ACES 1.0.2 update, if I remember correctly) when Resolve's built in S-Log3 IDT was for S-Gamut(3).

There's no conspiracy here. Let it go!

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555

Steve Shaw
 

I actually am not sure which 'Steve' you are asking (this new CML message workflow can be a bit difficult to follow at times...).

But, assuming it is me - send me the LUTs and I'll assess them for you.
(steve(at)lghtillusion.com)

We have Camera LUT generation built into to LightSpace, based on the camera manufacturer's own data (the camera manufactures we have included all assisted with this, so the data is accurate).
What is interesting is the LUTs our system generates are often 'different; the manufacturer's own LUTs, as they often add 'tweaks' to their LUTs to attempt make the image look better.
Not saying Arri do that, but a direct comparison will tell.

Steve

Steve Shaw
LIGHT ILLUSION
steve@...
+44 (0)7765 400 908
www.lightillusion.com

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